LED lighting systems are becoming more prevalent as replacements for existing lighting systems. LEDs are an example of solid state lighting and are superior to traditional lighting solutions such as incandescent and fluorescent lighting because they use far less energy, are far more durable, operate longer, can be combined in red-blue-green arrays that can be controlled to deliver virtually any color light, and contain no lead or mercury. As LEDs replace the typical fluorescent light fixtures found in many workplaces, as well as elsewhere, the present invention recognizes that an LED fixture in accordance with the present invention can be utilized to replace such fixtures, as well as, the separate emergency lighting fixture often employed in certain environments in conjunction with such fixtures.
One common fluorescent lighting fixture is a luminaire fixture 100 shown illustratively in FIG. 1. Fixture 100 may suitably comprise a 2′ by 4′ metal box or compartment 102 having a plurality of fluorescent bulbs 104, 106 and 108. While a 2′ by 4′ fluorescent fixture is discussed here as exemplary, it will be recognized that many other sizes of fluorescent fixture and various incandescent fixtures are also common. Each fluorescent bulb, such as bulb 108, is inserted in an electrical socket, and located within a reflective subassembly 110. The compartment 102 also typically has a reflective back surface, such as a white painted interior surface and a plastic cover mounted in a hinged door (not shown) which swings open to allow the bulbs to be easily accessed and changed. A typical office may have several such fixtures mounted to the ceiling of each room to provide room lighting. By way of example, an approximately 12′×20′ office might have three such fixtures mounted to its ceiling to provide ambient room lighting. Other facilities will employ a wide variety of known arrangements of lighting fixtures selected to meet the context and the environment to be lighted.
Taking our 12′×20′ office example, however, FIG. 2 shows a cutaway portion of a corner of such a room 200 having a door 202, and a luminaire fixture 204 mounted in the ceiling. Where the office is an interior office without windows or in a variety of other circumstances, an emergency lighting fixture such as fixture 206 of FIG. 2 may be required to be mounted above an exit door, such as the door 202 so that when power is lost during a power outage, a battery in fixture 206 will cause halogen lamps 207 and 208 to light allowing any occupants of room 200 to safely find the door 202 and leave the room. Halogen lamps typically have lighting characteristics very different from the light sources that light the room under normal conditions. While the room 200 is discussed as exemplary, it will be recognized that door 202 could be an exit door at the end of a long hallway, the door to leave an office, the door of a large interior conference room, a gymnasium, a mailroom or other work area, or the like. Similarly, an auxiliary lighting fixture could be mounted along an interior hallway, in a basement, or elsewhere, in addition to near an exit door. Regardless, in an arrangement like that shown in FIG. 2, the main light source goes off when power is lost and a separate auxiliary emergency backup goes on. Such an arrangement has several disadvantages including the extra cost of a separate auxiliary system, maintenance of such a system and the poor aesthetic appearance of some such systems, for example.